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Sadu V Hydroelectric Power Plant
'The Sadu V Plant is a hydroelectric power plant constructed on the Sadu River in Romania. The Sadu V Power plant has a head of 375 m and an was designed with an installed discharge of 9.6 m3/s. The installed capacity is 15.4 MW and the average yearly production of 30.5 GWh/an. The plant uses the a storage reservoir storing 6.3 million m3. History The development of the Sadu River for the production of hydroelectric power started in the 19th century. The Sadu I hydroelectric plant, with a capacity of 1.7 MW started operating in 1895 and the Sadu II plant, located upstream, with a capacity of 1.5 MW in 1907. Both were used for the power supply of the city of Sibiu. http://www.transelectrica.ro/1Despre/detaliiistoric.php?an=1907 1907 - punerea in functiune a hidrocentralei Sadu 2 In 1933, Professor Dorin Pavel Dorin Pavel - Plan général d'aménagement des forces hydrauliques de Roumanie - Bucharest 1933 proposed the construction of a chain of 4 additional hydroelectric plants for the use of the entire hydroelectric potential of the river. The most important was the Sadu V plant which developed the reach of the river between the Gâtul Berbecului Gorge and the confluence of with the Sădurel River. The Sadu V hydroelectric plant The construction of this plant started in 1949. Due to various constraints, in a first stage the plant was constructed as a run of river plant, using a temporary rockfill dam which was also designed to be the cofferdam for the main dam to be built in the future. This plant, constructed by the Sovromconstrucţia company, was put into operation on December 31, 1956. On December 31, 1956 when operation started, Sadu V was the second biggest hydroelectric power plant in Romania. The construction of the Negovanu dam was started in 1959 and completed in 1963. An extension of the power house by the installation of an additional turbine was completed in 1962-1963. This extension was unsuccessful and the additional turbine was eventually dismantled. Negovanu Dam The Negovanu dam is an double curvature concrete thin arch dam. The dam was designed by Professor Radu Prişcu (1921-1987). It is the first concrete arch dam in Romania, executed by Hydropower Construction Company, the future Hidroconstrucţia SA. At present, it is the 5th highest dam in Romania. The dam has a hight over the thalveg of 62.0 m and a radius of 78.0 m. the center angle of the crown radius being 110o, The crest elevation of the dam is 1158 m above sea level. The Negovanu storage has a normal level of 1154.20 m, a capacity of 6.5 million m3, a total surface of 72 ha and a maximum depth of 58 m. The dam is 19.0 m wide at its base and 3.5 at its crest.Lacul Negovanu Excess water spills over the top of the dam through an uncontrolled spillway with a capacity of 280 m3/s. The spillway has 5 openings of 5.80 m. The crest of the central opening is 40 cm lower than the others, for the evacuation of smaller discharges. A 150 m long diversion tunnel with a 2.20 by 2.60 m cross-section was constructed on the right bank to carry the Sadu River around the construction site. The tunnel was also used as a bottom outlet of the storage reservoir. A valve house equipped with two valves was constructed at the downstream end of the diversion tunnel. An additional outlet was constructed at the base of the dam. Main tunnel The inlet from Lake Negovanu is located at the right bank. It is protected by two racks and intake is controlled by a valve house equipped with 2 flat valves. The water is conducted through a 5350 m long feeder, out of which a 248 m long reinforced concrete pipeline having a diameter of 1.50 m, and a 5102 m long tunnel with a diameter of 1.80 m. A secondary inlet with a Tyrolean weir was built on the Sădurel River at elevation 1199 m, from which the water transferred to the main tunnel by a vertical shaft having also the role of secondary surge tank. Surge tank and penstock Surge tank is a vertical 31 m high shaft havind a diameter of 2.50 m. The lower chamber is created by a 24 m lateral tunnel and the upper chamber is a truncated cone, located above the shaft, extended to 9.85 m diameter. Downstream of the surge tank, at the end of the tunnel, a valve house was built, equipped with two butterfly valves. A 913 m long penstock with a diameter of 1.60 to 1.50 m conveys the water to the power house. Power house The Sadu V power house was initially equipped with 2 units of 7.7 MW Pelton turbines the installed discharge being 9.6 m3/s and the head 398 m. The average yearly production is 30.5 GWh. In 1963 an additional 12 MW Francis turbine with an installed discharge of 8.25 m3/s was installed. The performance was not satisfactory and the Francis group was dismantled. A tailrace channel starting at elevation 756 m connects the downstream stilling basin of the plant and Sadu River, which has been channeled upstream and downstream of the plant. Hidroconstrucţia 2005 ISBN-973-0-04208-X References Category:Hydroelectric power stations in Romania